Best time to run? Well... if you run naked, the best time is around 3 am.

Seriously, it hardly matters. I'm not a morning person and generally feel pretty crappy trying morning runs. I like to run at night. Though, in the winter, it can get a little depressing being so dark. Running late at night can make it more difficult to get to bed early. While I like night running most of the time, it can be tough for those people who have physically demanding jobs. If you are beat after a work day, then morning runs likely are a better choice.

What I find really difficult is to run late evening, and then morning on the next day. My 53 year old body really wants a full 24 hours of recovery between runs. It gets really pissed if I try shortening that time off. But I've tried 2-a-days before and found it workable if the mileage is reasonable.

What others have said. Run at the time that it can be a priority otherwise it will be too easy to neglect it or let other pressures in life push it out of the way.

I find it easiest to go for a run right after work in the afternoon. I'm not a morning person, so it would be terrible for me to run in the morning. I think it's very individual. Try to run different times every time and see how you feel about it.